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‘77 Yamaha RD400 – MotoRelic

Posted on August 5, 2016 by Andrew in Tracker. 67 comments


Written by Martin Hodgson.

The Seventies might have seen the introduction of the four-stroke Japanese superbikes but for a young lad looking to emulate his race day heroes it was a decade built on two-stroke smoke. The Kawasaki’s had brutal power and beautiful lines, the Suzuki’s offered a level of durability not known to most smokers but it was Yamaha’s RD range that offered the most charisma. Forget your heated grips, traction control and smooth fuel injection when you jump aboard an RD400 and get it up to speed it’s a white knuckle, eyes on stalks experience and that’s before you’ve even pinned the throttle. So when Sean Skinner of MotoRelic in Hamilton, Virginia, was approached by a friend to do a custom rebuild on his 1977 Yamaha RD400 he jumped at the opportunity. The end result is a screaming Yammy that looks better than any factory offering and delivers all of that two-stroke insanity in one hell of a beautiful package.


When Sean took on the job he hadn’t actually seen the RD in question, “If I had seen it in person before agreeing, I might have had second thoughts.” But never one to back down from a challenge and knowing the potential that lurks under the skin of the RD400 it was straight up on the lift for a full diagnosis. Take a look at any MotoRelic build and you can tell Sean is a planner; his bikes are comprehensively overhauled with no missed spots or last-minute half measures. So with the bike on the table and a clipboard in hand, a few minutes of poking and prodding let Sean know this patient was close to death, with a very long list of ailments. Not to worry as an order to two-stroke specialists in Nebraska, HVC cycles, had boxes of new goodies on the way and surgery could commence immediately. Then it was a matter of pulling the bike apart piece by piece to see where any structural damage might lay and boxing up the remaining good bits for later.


Like most two-stroke builds this one commences with the engine, rarely do you pull one apart that is in perfect running order and there would be no corners cut on the way to Yamaha nirvana. The 398cc, air-cooled, parallel twin has been given all the fruit and it starts with giving the cylinders a fresh hone. Then the short block was built up with all new bearings throughout before giving the rods a new set of pistons and rings to swing in anger. Those stunning DG replica heads from SCR didn’t come till later in the build after bike owner Rick was subjected to an adequate amount of peer pressure to get him to open his wallet for the big spend. But they are worth every cent, not only do they look incredible they deliver the performance to match having been developed to win at the Isle of Man and break land speed records.


To finish out the short block new seals and gaskets have been used throughout and an all new clutch fitted in anticipation of the extra ponies coming on board. Many of which come courtesy of the brilliant DG expansion chambers in the classic Yamaha design. So good are these pipes that the original 40hp figure gets a bump of up to 13hp more with many of those stallions coming earlier on in the rev range for a less peaky motor and all with a nice 10lb weight saving. To get the induction side up to spec a Y-pipe draws air through a K&N filter that gives an all mighty roar when the throttle is cracked. While feeding the beast the oily mix the standard Mikuni carbs have been re-jetted and tuned to match the other modifications. It’s all been finished off with a fresh coat of paint and “that killer wrinkle powdercoat done by Daniel at Appalachian Paint and Powder.”

With a belter of an engine ready to go Sean had to work out exactly how he’d approach the rest of the build to do it justice and handle the extra power. “I was torn on what to do with the “look” of the frame. Rick wanted to keep the bike looking mostly stock and have a small tapered tail section.” He found the solution in shortening the frame and adding the up-kicked hoop that doubles as a seat stop and as a mounting point for the tail section. The tail-piece itself is all Sean’s work and while it utilises some of the classic RD400 lines, the curves over straight lines offer a stylish modern interpretation. It also acts as a functional rear fender and the underside is contoured to match the lines of the rear tyre. “Hand fabricating the seat pan and tail to match was a challenge due to the fact that the battery and oil tank are in the stock location.”

With the body work off, the entire frame, swingarm and triple trees having been given a coat of gloss black so as not to take attention away from the mouth-watering body work and engine. “As always, I leave the paint work on the tins to Craig at Homeward Bound Motorcycle.” From his small shop Craig does some incredible work with some of the most striking paint jobs on traditional American bobbers, but he hit every mark with the RD with a double blue combination that is set off with white and black graphics. Under direct sunlight the darker of the blue shades appears to morph into the lighter colour that gives the logos an almost 3D effect that just cannot be captured even with the camera technology of 2016. With such an incredible paint job understated black was chosen for the seat’s leather, “Counter Balance Cycles did a fantastic job covering the seat. I’m sure it was not fun working around my design.”


While the RD400 was known for its fast steering and quality brakes in 1977 nearly four decades have passed and Sean wanted to bring the bike into the modern era without taking away from its classic lines. Rather than follow the crowd and fit USD forks he instead found a solution to his dual needs “I opted for an early generation R6 style. It is wider and has larger tubes than stock but isn’t overpowering to the bike”. Before fitting up the late-model suspension the forks have been given a full rebuild to match the different weight of the RD and shaved of any unnecessary brackets and bolt holes. With Rick wanting to keep the standard wheels a solution to adapting them to the new forks and finding a brake combination to work was left in the hands of machinist Ryan Dzurilla. “He came out and measured up for spacers and an adapter to mount the FZR rotor. It worked like a dream and after sizing up some bearings it went together flawlessly!” The old ‘70s wheels get a set of modern Continental ContiPro tyres because cross ply don’t fly on an angry two-stroke like this!<


To work with the new R6 front end and control the rear the twin shock setup remains with a pair of adjustable remote reservoir items tasked with the job. Speedmoto headlight brackets and a single Koso speedo clean up the front end remarkably well and with the new clip-ons only wearing the barest of necessities the all business theme of the build rules throughout. A powerful and lightweight Shorai battery sits in the stock location and to complete the build a set of HVCcycles brilliant rearsets do the business. Rolled out of the workshop door it’s hard to know whether Rick stood back to admire his new possession or jumped on and screamed off down the road but either way Sean’s got his mate covered with an incredible build. “That sound and smell brings back fun memories for anyone who has thrown a leg over a 2 stroke motorcycle as a kid” and those glorious years of the ’70s come flooding back.


[MotoRelic: WebFacebook – Instagram | Photos by Nubbs Sugrue]

  • Tomatenfisch

    Very nice bike. But why blowing the exhaust to the license plate?
    I would change.

    • MotoRelic

      Its about 3in away to the right. Before you think about changing it, consider perception.

      • It’s amazing how people become experts on the bike after looking at a few photos for 30 seconds. The assumption that they somehow know more than the builder, who’s been living with it for months and months, always blows my mind. Think before you speak? What about think before you type?

        • acuity

          It’s amazing how there are no photos that can visually answer this guy’s simple question and comment.

          The photo’s in question do appear to do exactly what he commented on. How is he supposed to know whether is 0, 3, 15 or whatever inches away. Maybe a head on or back on view?

          @motorelic, before being a d!ck for no apparent reason, re-read his first sentence. Then check the tone of the 2nd and 3rd, I would guess he is a non-native english speaker. And lastly, take your own advice, perception is key, so tell me what photo provided in the article makes it plain that it is 3 inches to the right?

          @Pipeburn_Andrew:disqus – Yes, what about think before you type? Did your bruised ego get the better of you? Do you have a photo from head on or back on that you simply could have posted to clear up the confusion rather than piling on the d!ck train?

          • Dave Coetzee

            My exact thoughts!

          • MotoRelic

            Holy smokes! Theres no reason to call me a dick and im rather confused on why my recommendation to consider perception is so frownd upon.

          • acuity

            It’s about respect. I think Andrew’s follow up showed the tone you set in your response. And yes, while it may be viewed many ways, Andrew decided to run with it negatively.

            That in conjunction with your attitude displayed towards Dave below and his comment, then your subsequent sobering up when Mule offered much the same point and you went into the technical details of the seat tells a lot. Non established builders/critics can eat your ass, while established ones get sucked.

            And all it would have taken was one simple photo…

          • MotoRelic

            Respect?? Jesus im so done with you. You can eat all the ass you want. And suck whatever you’re referring to.

          • Fast2Furious

            Wow. Thin skinned much. Maybe you don’t have the temperament to be a custom bike builder.

          • MotoRelic

            Are you an actual custom motorcycle builder? Can you justify your statement? As far as I know you are nothing more than the common forum troll that smears their opinion on anyone who will listen. This forum would be much more useful if it had actual builders, who bled for the machine they created, offering advice or useful commentary. What’s the saying? Those that can, do. and those that can’t, teach. I think that rings the loudest on this forum. The backhanded compliments are sickening to read over and over and over. Thin skinned? no. People that have passion for what they do normally have strong feelings about it.

          • Fast2Furious

            You’re the one who started using terms like eat ass and suck whatever. which goes way beyond passion for what you do. Also your lack of respect for teachers is absolutely stunning even for you.

          • Adam Rykos

            What a damn baby. I like the bike, but you suck.

          • Darrick B

            I love the bike, especially the paint.

            But I’m mainly here for the d!ck train.

          • MotoRelic

            toot toot!

        • brownroundtown

          Ladies please! Stop swinging those handbags or you’ll hurt somebody! Let’s just all agree it’s a cool bike eh?!?

          • Fast2Furious

            Why has this comment been allowed to stand the use of the term ladies is clearly meant as a pejorative and is intended to ridicule and belittle both men and women.

          • the watcher

            God help us!

          • MotoRelic


          • Fast2Furious

            Is your comment supposed to mean something because if it is than your point is more than just a little bit elusive.

          • I’m of the opinion that “God help us!” was meant to convey exasperation at the silliness of this whole argument.
            Tomatenfisch’s comment was legit and not addressed with a photo and things got out of hand.
            It’s a great looking bike but I still want to see a goddam front fender on a custom bike. Some day.

          • brownroundtown

            Do you have to practice being a douchebag or does it just come naturally?

          • Fast2Furious

            You sound like the quite the expert on douchebags so I’ll leave that to you. I’m not surprised that the only response you have to being called out for your hateful comments is to personalize your answer and start calling names.

          • brownroundtown

            ‘my hateful comments’?? Seriously?? Man, you need to lighten up. But rather than descend into animosity, let’s call a truce and just concentrate on the bikes eh?

          • Fast2Furious

            I don’t respond well to name calling or being told what to do and I’m sure you don’t either but seriously you need to stop disrespecting women by referring to men as “ladies”. Period.

          • the watcher

            “I don’t respond well to…..being told what to do”, and “you need to stop….” all in one sentence. Genius.

          • Fast2Furious

            Parse my words all you want to and insult me as much as you like since you seem to enjoy it so much but it doesn’t change the fact your original comment used the term “ladies” as a means to shame, insult, degrade and bully others.

      • Tomatenfisch

        Unbelievable what a simple question does that. Just because I do not like smoke on the plate. uaahhh. I’m going to ride my motorcycle.
        The Yamaha is still very nice with lots of great details. Unscrew all and a board seat as I’ve already seen enough.

  • thumpthump

    why does this look so much heavier than the original? something about the wheel/tire combo? did rear travel get reduced? looks a bit like a german shepherd, slouching.

    • Jester the Clown

      I thought that.
      The original was a tiny, little thing.
      Perhaps it’s a combination of things.
      The tyres look oversized, the exhaust, although I’m sure the dimensions are correct re. performance, also look oversized and the seat looks about twice the depth of the original.
      And, as usual, its tail’s been chopped off.

    • They had pretty short rear swing arms but looooong seats which made it look longer, more sleek, and more balanced. By chopping more than half the seat off it really screws up the proportions (not in a good way IMO). The seat thickness is basically the same as stock. RD’s are one of those motorcycles that look right-on from the factory. Not sure why you would hack the back half off.

    • MotoRelic

      Eh its hard to say. The wheels are stock and the ride height is stock. Maybe with the large pipes and slightly over sizes tires she looks big boned 🙂 but nevertheless its very fun to ride and considerably lighter than stock.

      • Soapy Loofah

        Shortening of the seat and the small tail section give the bike a compact feeling horizontally, but the vertical mass is unchanged so it may appear to be larger than the original. Now having said that, I’m not suggesting it’s unappealing, just different.

        As to the rest of the build, it succeeds in my eyes. It was a fun bike to begin with (having owned a Daytona Special, along with every other US RD variation Yamaha came up with right up to the RZ and even an RG 500), and lighter with more useable HP can only have improved this classic.

        Oh, and as for the seat – the fact that you didn’t slap thin-assed plank on there tells me volumes about your ability to differentiate between usefulness and fad. Well done.

        • MotoRelic

          Thanks i appreciate it!

    • JayJay

      Find it strange as well, think it has to do with the black engine and exhaust. I personally like it.

  • the watcher

    Doesn’t do much for “disqus” I know, but the nicest builds require the fewest words. Love it. The seat? He doesn’t want to take you, and you don’t want to go.

  • Andy Rappold

    Ooh yeah , Baby!
    That is one freaking awesome build.

    • MotoRelic

      Thank you sir!

  • Harrison Fiddis

    The left side of the bike must be ugly as sin lol. Actually just curious if all the engine covers were coated in that textured stuff. I like it.

    • MotoRelic

      Haha the left side is identical……or is it?…
      Just the side covers were done in the wrinkle. I really like it and will use it again!

      • ecosse

        sweet build all around. love the seat and a relief from the god-awful “brat seat” crap.

        • MotoRelic

          If i could upvote this more than once i would! Thanks ecosse!

  • Dave Coetzee

    Exciting build and great type of bike featured on Pipeburn.I’d like to see a photo-shopped, restyled pic of the seat – about 1/3 the thickness of this seat and perhaps the headlight lowered a bit.

    • MotoRelic

      Oooor you could get out from behind the photoshop and build one how you like 😆 The design you are wishing to see would look like any other cookie cutter build.

    • Ye, the seat looks a bit pillowy. I like modified bikes with original paint. That looks cool. But not the original carbs. 34’s please. I’ve probably torched a dozen kick levers just like that. Good job. 🙂

      • Dave Coetzee

        I appreciate the comment support Mule. I also enjoy retaining the original paint-job where possible, as you may have noticed on my all inc.<$1K build (that is not the subject of this review and definitely not in the same league)

      • MotoRelic

        Thanks Mule! It could definitely benefit from some better carbs. The kicker was a must. Tearing the meat off your ankle is not cool haha! The seat is deceiving. Its tall because it has to clear the stock oil fill and battery location. Theres about 2in of actual padding 😆

        • Jon Payne

          The mount points of the items can be modded to get a much lower seat hight, can send pics if wanted.

          • MotoRelic

            I appreciate that but the owner of the motorcycle wanted the battery and oil fill cap left in the stock location. I wish i had a pic to show how it mounts. Its no higher than stock really.

  • ShS

    Vero stile!

  • Jon Payne

    Couple of quick questions, is the rear fender a modded piece from a 78 Rd, why the high mounted reservoir on the front brake, and why no fork brace? Thanks

    • MotoRelic

      I hand made the tail section, the seat and modified the frame to accept it. The front forks are larger than stock and do not flex. The reservoir is high to pluck at the ocd in all of us.

      • MotoRelic

        Another view

      • Why wouldn’t you stretch that photo down to show the clearance of the pipe from the license plate in order to kill two birds with one stone?
        Would love to see the front brake resevoir sit down beside the clock if that’s possible.
        And the brake light seems like a forties Harley item. French in an LED brakelight to that very cool tailpiece and I would just start applauding and throwing money at you.
        None of this matters now. Fantastic bike. Bravo!

        • MotoRelic

          Oh believe me, if i could show a freakin photo of how the exhaust sits, i would! Mother of god, i would!! LOL!

  • Lowflying

    I love these bikes in general. Once I got over my initial reaction, which was outrage at the rear being chopped, I could see that this looks pretty cool. That stubby rear works, and my girlfriend hates riding on the back of my RZ350 so she probably wouldn’t want to ride on this either! Loving the paint and details. In my nitpicking opinion this bike is worse off for not having a front fender, as it’s not a tracker or a festering (sorry, my meds are wearing off) old shovel hardtail. Just my worthless opinion, but my therapist says I’ll feel better for getting it off my chest…

    Long live strokers…;-)

  • MotoRelic

    The owner of the bike sent this to me so I could post it for him. Just so you all could sleep better at night. Thats if you sleep.

    • 2StrokeFreak

      Amazing! Respect! I love this bike!
      (To keep that fire alive, if you would mount a licence-plate from Austria, it would blow against it ;-P)

      • MotoRelic

        Haha thanks! Luckily the DG exhaust it fully adjustable 😉

  • Manx Ryan

    It looks like a well thought-out and executed build. Mule makes me laugh; complaining about most builds having seats too thin, and now this one is too “pillowy’.

    Bike looks an absolutely blast to ride, no extreme geometry changes which is nice to see for once!

    I hate to say it but the photos do not do the build justice at all, far too dark and contrasty and I think that adds to the “heavy’ look of the bike.

    • MotoRelic

      Thanks Manx, I guess you just cant make some people happy. Like Goldilocks looking for juuuuust riiiiiight. “This ones too pillowy……this one toooo thin.

      Im not sure why the photos look this way. The originals do not. Ah well glad ya like the bike

      • Jester the Clown

        Photoshop is your friend!
        A few seconds work; the images are transformed and so is the overall impression of being overweight.
        It still looks a bit plump compared to the original but nowhere near as much as it does in these photographs.
        Doesn’t help the chopped off tail though . . . !

      • Manx Ryan

        Haha very true, it’s the reason that (as an amateur) I’d never put my build up on Pipeburn, after all the effort it would be heartbreaking to see it torn to shreds by the trolls.

        I’d suggest that it’s probably partially due to the very small image size on the site, you’ll see a lot more detail when they are displayed on large screens but when they compress and resize the images a lot of that detail is lost.

  • Really dig the level of detail and finish in that tail piece, inside and out ! Not too many folks take that sort of care, nice one. Wondering if those back faces of it would lend themselves to having one-off stop light and indicators integrated into them….

  • guvnor67

    Fabulous! I personally like the short, stubbie look, makes it look like it’s ready to launch. The colours and textures work very well, and I like the tail heaps more than the one that was fitted to my old RD350LC, which is yet another bike I regret letting go. Well done!

  • Tom Lendman

    “Pillowy seat”, exgirlfreind maybe?

  • Roth

    Wow, you are exactly the people I want to look at my bike! I want you to criticize my bike. I am a builder and welcome talk

  • Sherb

    I have the same 1977 RD (same DG pipes, they haven’t changed those much!), rode it home from my ship in Charleston S.C., via back roads of VA, WV and OH, to Northwest Lower Michigan in 1981. This might just be the inspiration I need to bring it back. I have never been able to part with it! The only bike I ever truly desired.